ascorbic-acid and Lymphoma--Large-B-Cell--Diffuse

The Ten Eleven Translocation (TET) enzymes have been found to be mutated in both diffuse large B-cell (DLBCL) and peripheral T-cell (PTCL) lymphomas resulting in DNA hypermethylation. Recent studies in embryonal stem cells showed that ascorbic acid (AA) is a cofactor for TET with a binding site at the catalytic domain, and enhances TET activity. We hypothesized that AA could potentially enhance TET activity in lymphoma cells to cause DNA demethylation, reactivate expression of tumor suppressor genes and enhance chemosensitivity. We demonstrate in vitro that AA treatment of DLBCL and PTCL cells using AA concentrations achievable intravenously increased TET activity leading to DNA demethylation. This epigenetic effect is independent of hydrogen peroxide. AA treatment increased the expression of SMAD1, a tumor suppressor gene known to be suppressed by methylation, and increased chemosensitivity of lymphoma cells. Twenty-nine percent (10/34) of unselected lymphoma patients had plasma AA levels that were deficient suggesting an additional clinical mechanism of TET hypofunction. These data indicate that AA has the potential to modify TET function in lymphoma and enhance chemosensitivity. In addition, the AA deficiency seen in some patients may further impair TET function and contribute to resistance. Clinical trials testing intravenous AA with chemotherapy are warranted.

Topics: Ascorbic Acid; Cell Line, Tumor; Gene Expression Regulation, Neoplastic; Humans; Lymphoma, Large B-Cell, Diffuse; Mixed Function Oxygenases; Proto-Oncogene Proteins; Up-Regulation

Transmembrane reduction of extracellular oxidants by K562 and U937 leukemic cells was stimulated by catalytic amounts of ascorbate or dehydroascorbate. This stimulation was not due to transport of ascorbate in different redox states in and out of the cells. The membrane redox cycle was strictly dependent on the presence of the cells at every stage, and showed high affinity for ascorbate with simple linear kinetics. Metabolic inhibitors and sulfhydryl reagents inhibited this stimulation. Ascorbate uptake was also dependent on oxidation, but in a very different manner and with much lower affinity for ascorbate. The uptake was non-saturable in the concentration range used. There was some release of ascorbate from the cells, which cannot account for an appreciable part of the reduction of extracellular electron acceptors.

Topics: Ascorbic Acid; Biological Transport; Cell Membrane; Culture Media; Dehydroascorbic Acid; Electron Transport; Ferricyanides; Humans; Kinetics; Leukemia, Erythroblastic, Acute; Lymphoma, Large B-Cell, Diffuse; Oxidation-Reduction; Tumor Cells, Cultured

A case of reticulum cell sarcoma apparently successfully treated with mega ascorbic acid therapy is described briefly. While the patient continued a large maintenance dose of ascorbic acid, a papillary thyroid carcinoma developed clinically. The role of ascorbic acid in the body resistance to cancer and in tumour prevention is discussed.

Topics: Adult; Ascorbic Acid; Carcinoma, Papillary; Humans; Lymphoma, Large B-Cell, Diffuse; Male; Thyroid Neoplasms

Topics: Ascorbic Acid; Diet; Humans; Lymphoma, Large B-Cell, Diffuse; Neoplasms

This series presents further evidence for an association between reticulosis of the intestine and steatorrhoea. Although some patients have a definite past history of gluten enteropathy, it seems likely that in certain patients the reticulosis itself is the primary cause of the steatorrhoea.

Topics: Ascorbic Acid; Blood Transfusion; Body Weight; Bone Marrow Examination; Celiac Disease; Diet; Diet Therapy; Fats; Feces; Folic Acid; Humans; Intestinal Neoplasms; Intestinal Perforation; Intestine, Small; Iron; Lymphoma, Large B-Cell, Diffuse; Lymphoma, Non-Hodgkin; Nandrolone; Neomycin; Neoplasms; Pathology; Prednisone; Sarcoma; Steatorrhea; Surgical Procedures, Operative; Vitamin A; Vitamin B 12; Vitamin B Complex; Vitamins; Water-Electrolyte Balance